Merge pull request #220 from FKREISE/dynamicinjected

Add @DynamicInjected property wrapper

Sources/Factory/Factory.docc/Additional/Migration.md

@@ -97,7 +97,7 @@ Finally, you can also use the @Injected property wrapper. That's changed too, an
 ```
 The @Injected property wrapper looks for dependencies in the shared container, so this example is functionally identical to the `Container.shared.service()` version shown above.
 
-See ``Injected``, ``LazyInjected``, ``WeakLazyInjected``, and ``InjectedObject`` for more.
+See ``Injected``, ``LazyInjected``, ``WeakLazyInjected``, ``DynamicInjected`` and ``InjectedObject`` for more.
 
 ```swift
 // Factory 1.0 version for reference

Sources/Factory/Factory.docc/Advanced/Design.md

@@ -146,7 +146,7 @@ class ContentViewModel: ObservableObject {
 ```
 Factory 2.0 also updates the syntax to use keyPaths, much like SwiftUI environment variables.
 
-See ``Injected``, ``LazyInjected``, ``WeakLazyInjected``, and ``InjectedObject`` for more.
+See ``Injected``, ``LazyInjected``, ``WeakLazyInjected``, ``DynamicInjected`` and ``InjectedObject`` for more.
 
 ## Breaking Changes
 

Sources/Factory/Factory.docc/Basics/Containers.md

@@ -136,7 +136,7 @@ class ContentViewModel: ObservableObject {
 ```
 We now have an instance of `cachedService` in our view model, as well as a reference to the same instance cached in `MyContainer.shared.manager`.
 
-See ``Injected``, ``LazyInjected``, ``WeakLazyInjected``, and ``InjectedObject`` for more.
+See ``Injected``, ``LazyInjected``, ``WeakLazyInjected``, ``DynamicInjected`` and ``InjectedObject`` for more.
 
 ## Registration and Scope Management
 

Sources/Factory/Factory.docc/Basics/Resolutions.md

@@ -69,7 +69,7 @@ struct ContentView: View {
     }
 }
 ```
-See ``Injected``, ``LazyInjected``, ``WeakLazyInjected``, and ``InjectedObject`` for more.
+See ``Injected``, ``LazyInjected``, ``WeakLazyInjected``, ``DynamicInjected`` and ``InjectedObject`` for more.
 
 ### Global Keypath Resolution from Shared Container
 Factory provides two global functions that utilize keypaths for resolution. 

Sources/Factory/Factory/Injections.swift

@@ -253,6 +253,50 @@ import SwiftUI
 
 }
 
+/// Convenience property wrapper takes a factory and resolves an instance of the desired type.
+///
+/// Property wrappers implement an annotation pattern to resolving dependencies, similar to using
+/// EnvironmentObject in SwiftUI.
+/// ```swift
+/// class MyViewModel {
+///    @DynamicInjected(\.myService) var service
+///    @DynamicInjected(\MyCustomContainer.myService) var service
+/// }
+/// ```
+/// The provided keypath resolves to a Factory definition on the `shared` container required for each Container type.
+/// The short version of the keyPath resolves to the default container, while the expanded version
+/// allows you to point an instance on your own customer container type.
+///
+/// - Note: The @DynamicInjected property wrapper will be resolved on **access**. In the above example
+/// the referenced dependencies will be acquired each time the property is accessed.
+@propertyWrapper public struct DynamicInjected<T> {
+
+    private let reference: BoxedFactoryReference
+
+    /// Initializes the property wrapper. The dependency is resolved on access.
+    /// - Parameter keyPath: KeyPath to a Factory on the default Container.
+    public init(_ keyPath: KeyPath<Container, Factory<T>>) {
+        self.reference = FactoryReference<Container, T>(keypath: keyPath)
+    }
+
+    /// Initializes the property wrapper. The dependency is resolved on access.
+    /// - Parameter keyPath: KeyPath to a Factory on the specified Container.
+    public init<C: SharedContainer>(_ keyPath: KeyPath<C, Factory<T>>) {
+        self.reference = FactoryReference<C, T>(keypath: keyPath)
+    }
+
+    /// Manages the wrapped dependency.
+    public var wrappedValue: T {
+        get { return reference.factory().resolve() }
+    }
+
+    /// Unwraps the property wrapper granting access to the resolve/reset function.
+    public var projectedValue: Factory<T> {
+        get { return reference.factory() }
+    }
+}
+
+
 /// Basic property wrapper for optional injected types
 @propertyWrapper public struct InjectedType<T> {
     private var dependency: T?

Tests/FactoryTests/FactoryInjectionTests.swift

@@ -27,6 +27,13 @@ class Services3 {
     init() {}
 }
 
+class Services4 {
+    @DynamicInjected(\.myServiceType) var service
+    @DynamicInjected(\.mockService) var mock
+    @DynamicInjected(\CustomContainer.test) var test
+    init() {}
+}
+
 class Services5 {
     @Injected(\.optionalService) var service
     init() {}
@@ -55,6 +62,7 @@ extension Container {
     fileprivate var services1: Factory<Services1> { self { Services1() } }
     fileprivate var services2: Factory<Services2> { self { Services2() } }
     fileprivate var services3: Factory<Services3> { self { Services3() } }
+    fileprivate var services4: Factory<Services4> { self { Services4() } }
     fileprivate var servicesP: Factory<ServicesP> { self { ServicesP() }.shared }
     fileprivate var servicesC: Factory<ServicesC> { self { ServicesC() }.shared }
 }
@@ -124,6 +132,13 @@ final class FactoryInjectionTests: XCTestCase {
         XCTAssertEqual(services.test.text(), "MockService32")
         XCTAssertNotNil(services.$service.resolvedOrNil())
     }
+
+    func testDynamicInjection() throws {
+        let services = Services4()
+        XCTAssertEqual(services.service.text(), "MyService")
+        XCTAssertEqual(services.mock.text(), "MockService")
+        XCTAssertEqual(services.test.text(), "MockService32")
+    }
 
     func testLazyInjectionOccursOnce() throws {
         let services = Services2()
@@ -233,6 +248,14 @@ final class FactoryInjectionTests: XCTestCase {
 
         XCTAssertNil(service.service)
     }
+
+    func testDynamicInjectionResolve() throws {
+        let object = Container.shared.services4()
+        let oldId = object.service.id
+        // should have new instance
+        let newId = object.service.id
+        XCTAssertTrue(oldId != newId)
+    }
 
     #if canImport(SwiftUI)
     @available(iOS 14, *)